FBD for car slowing down?

  • Thread starter alaa amed
  • Start date
  • #1
19
0

Homework Statement



A car is coasting to the right and slowing down. Neglect air resistance
Draw free body diagram.

Homework Equations


N/A

The Attempt at a Solution



I drew the normal and the force of gravity equal and opposite of each other in the vertical direction. However, I am little confused about the direction of the force of friction. I know that the velocity vector should be pointing to the right and the acceleration vector should be pointing to the left since the car is slowing down, but what does that mean for the force of friction?

Thanks, [/B]
 

Answers and Replies

  • #2
nrqed
Science Advisor
Homework Helper
Gold Member
3,737
279

Homework Statement



A car is coasting to the right and slowing down. Neglect air resistance
Draw free body diagram.

Homework Equations


N/A

The Attempt at a Solution



I drew the normal and the force of gravity equal and opposite of each other in the vertical direction. However, I am little confused about the direction of the force of friction. I know that the velocity vector should be pointing to the right and the acceleration vector should be pointing to the left since the car is slowing down, but what does that mean for the force of friction?

Thanks, [/B]
Hint: ## \vec{F_{net}} = m \vec{a} ##
 
  • Like
Likes haruspex
  • #3
CWatters
Science Advisor
Homework Helper
Gold Member
10,532
2,298
Perhaps consider a wheel subject to braking. Which way is the wheel trying to slide relative to the road. What does that tell you about the direction of the friction force?
 
  • #4
haruspex
Science Advisor
Homework Helper
Insights Author
Gold Member
2020 Award
35,561
6,442
Perhaps consider a wheel subject to braking. Which way is the wheel trying to slide relative to the road. What does that tell you about the direction of the friction force?
While that works, I recommend nrqed's hint since that does not depend on the ultimate cause of the slowing. It encompasses axle friction and rolling resistance.
.
 

Related Threads on FBD for car slowing down?

Replies
14
Views
5K
Replies
13
Views
7K
  • Last Post
Replies
1
Views
1K
  • Last Post
Replies
14
Views
3K
  • Last Post
Replies
12
Views
3K
Replies
1
Views
1K
  • Last Post
Replies
13
Views
4K
Top